EFFICIENT NON-LINEAR FINITE ELEMENT SHELL FORMULATION INVOLVING LARGE STRAINS.

A previously presented finite-element shell formulation is extended to the application of large strains. The finite elements are those based on the concept of degenerated solids which is used in non-linear finite element programs. The constitutive equation of hyperelastic incompressible material is adopted to the Mooney-Rivlin law. The additional state variable, the hydrostatic pressure, which occurs for incompressible materials is eliminated on element level using the plane stress condition. Attention is drawn to the efficient calculation of the element matrices by applying a layer concept. The effectiveness of the proposed total Lagrangian formulation is demonstrated in example problems.